A CRISPR screen for RBC regulators Hemoglobin in red blood cells (RBCs) carries oxygen to the tissues. Sickle cell disease is an inherited condition that involves abnormal hemoglobin. Current treatments entail modulating the level of fetal hemoglobin expression. Grevet et al. performed a CRISPR-Cas9 screen for regulators of fetal hemoglobin in RBCs and identified heme-regulated eIF2α kinase (HRI). Depleting the kinase in RBCs led to an increase in fetal hemoglobin levels and reduced sickling of cultured human RBCs. Thus, HRI may be a therapeutic target for sickle cell disease and other hemoglobin disorders. Science, this issue p. 285 HRI kinase represses expression of fetal hemoglobin and provides a potential target for sickle cell disease treatment. Increasing fetal hemoglobin (HbF) levels in adult red blood cells provides clinical benefit to patients with sickle cell disease and some forms of β-thalassemia. To identify potentially druggable HbF regulators in adult human erythroid cells, we employed a protein kinase domain–focused CRISPR-Cas9–based genetic screen with a newly optimized single-guide RNA scaffold. The screen uncovered the heme-regulated inhibitor HRI (also known as EIF2AK1), an erythroid-specific kinase that controls protein translation, as an HbF repressor. HRI depletion markedly increased HbF production in a specific manner and reduced sickling in cultured erythroid cells. Diminished expression of the HbF repressor BCL11A accounted in large part for the effects of HRI depletion. Taken together, these results suggest HRI as a potential therapeutic target for hemoglobinopathies.

中文翻译：

---

以域为中心的 CRISPR 筛选将 HRI 识别为人类红细胞中的胎儿血红蛋白调节剂

红细胞 (RBC) 中红细胞 (RBC) 中的血红蛋白的 CRISPR 筛选将氧气输送到组织。镰状细胞病是一种涉及异常血红蛋白的遗传性疾病。目前的治疗需要调节胎儿血红蛋白的表达水平。格雷维特等人。对红细胞中胎儿血红蛋白的调节剂进行了 CRISPR-Cas9 筛选，并确定了血红素调节的 eIF2α 激酶 (HRI)。消耗红细胞中的激酶会导致胎儿血红蛋白水平升高，并减少培养的人类红细胞的镰状化。因此，HRI 可能是镰状细胞病和其他血红蛋白疾病的治疗靶点。科学，本期第 3 页。285 HRI 激酶抑制胎儿血红蛋白的表达，并为镰状细胞病治疗提供了潜在的靶点。增加成人红细胞中的胎儿血红蛋白 (HbF) 水平可为镰状细胞病和某些形式的 β-地中海贫血患者提供临床益处。为了在成人红细胞中识别潜在的可药用 HbF 调节剂，我们采用了一种以蛋白激酶结构域为中心的基于 CRISPR-Cas9 的遗传筛选，并具有新优化的单向导 RNA 支架。筛选发现了血红素调节抑制剂 HRI（也称为 EIF2AK1），一种控制蛋白质翻译的红细胞特异性激酶，作为 HbF 阻遏物。HRI 消耗以特定方式显着增加了 HbF 的产生，并减少了培养的红细胞中的镰状细胞。HbF 阻遏物 BCL11A 的表达减少在很大程度上是 HRI 耗竭的影响。综合起来，